Lift means



.1. M. LAWSON April 5, 1960 LIFT MEANS 4 Sheets-Sheet 1 Filed March 31, 195B INVENTOR, JOSEPH M. LAWSON April 1960 J. M. LAWSON 2,931,461

LIFT MEANS Filed March 31, 1958 4 Sheets-Sheet 2 JOSEPH M. LAWSON April 5, 1960 J. M. LAWSON 2,931,451

LIFT MEANS Filed March 31, 1958 4 Sheets-Sheet 3 IN VEN TOR, JOSEPH M. LAWSON MWMMJJ April 5, 1960 J. M. LAWSON 2,931,461

LIFT MEANS Filed March 31, 1958 V 4 Sheets-Sheet 4 FIG.5

INVENTOR, JOSEPH M. LAWSON nite LIFT MEANS Application March 31, 1958, Serial No. 724,999

Claims. (Cl. 187-46) This invention relates to certain new and useful improvements in lift means or hoists, and particularly of the type adapted for use in connection with lumber operations, as for example in the elevation of kiln cars for introduction into a suitable kiln.

Tie lift means of the present invention are adapted for numerous usages, and the particular adaptability of the present lift means for use in connection with lumber operations is illustrative thereof.

Many forms and kinds of lifts or hoists have been heretofore devised, some of which have employed cable means for effecting lifting of the device, usually embodying a difficulty in adequately providing for drive to equally tension the cable means in order to accomplish lifting without tilting. Similarly, hydraulic means have been employed for the purpose of effecting lift, and such hydraulic means have inherently been faced with the difficulty of unequal lifting being exerted by the means due particularly to lag in one or more of the hydraulic cylinder and piston assemblies involved in such devices.

The present invention seeks to overcome the difficulties which have been heretofore encountered in lift devices, and to provide a lift means in which the lifting force exerted on the parts of the lift is automatically equalized through the arrangement of the present device. This purpose is accomplished by providing a combination of hydraulically operated means for energizing a cable lift, and comprising hydraulic cylinder and piston assembly means, which carries a bank of pulleys on the distal end of the piston rod with the cables from the respective corners of the lift being passed around the pulley bank and suitably anchored so that the thrust exerted by the cylinder and piston assembly means is equally exerted upon all of the cables of the device. These operating devices are mounted in and carried upon the carriage of the lift means of the present invention and travel therewith during raising and lowering of such carriage.

The principal object of the present invention is to provide a new and novel lift means.

A further object of the invention is to provide such a lift means which comprises a cable lift in which the cables are operated by hydraulically powered units.

A further object of the invention is to provide such lift means in which hydraulic cylinder and piston assemblies are disposed for exerting opposite thrust, each of the assemblies carrying a bank of pulleys, and with the cables connected to the corners of the lift means being respectively passed about each of the pulley banks in order that the opposing thrusts of the cylinder and piston assemblies will be exerted upon all the cables equally.

A further object of the invention is generally to improve the design, construction and etficiency of lift means.

The means by which the foregoing and other objects of the present invention are accomplished and the manner of their accomplishment will be readily understood tates Ill) from the following specification upon reference to the accompanying drawings, in which:

Fig. 1 is a top plan view of the lift means of the present invention.

Fig. 2 is an end view of the lift means.

Fig. 3 is a fragmentary sectional view taken as on the line III-Ill of Fig. 1.

Fig. 4 is a sectional view taken as on the line, IVIV of Fig. 1.

Fig. 5 is a somewhat diagrammatic plan view illustrating the device in an intermediate lift position.

Fig. 6 is a somewhat diagrammaticend view illustrating the device in the position of Fig. 5.

Fig. 7 is a similar somewhat diagrammatic plan view. illustrating the device in full elevated position.

Fig. 8 is a diagrammatic end view illustrating the device in the position of Fig. 7; and

Fig. 9 is a wiring diagram illustrating the system for energizing the lift means.

Referring now to the drawings in which the various parts are indicated by numerals, and in which a pres ferred embodiment of the present device is shown, there is included a plurality of lift posts 11., 13, which are positioned in spaced apart relation to define a substantially quadrilateral area. Suspended from the posts for vertical shift along the posts are a pair of composite frame members, including a front frame member 15 which spans between front posts 11, and a rear frame member 17 which spans between rear posts 13. Each of the frame members.15, 17 is preferably formed of suitable structural members, such as the opposed channel members which are illustrated in the present drawings. These structural members are respectively interconnected in order to form a rigid frame member for the device.

Seated upon, spanning between and rigidly secured to the frame members 15, 17 is the lift carriage 19 of the present invention. Lift carriage 19 comprises front and rear transverse members 21, 22, each preferably formed of suitable structural members such as the channel iron shown, and a pair of longitudinal side members 24, 25, which are preferably formed as of I-beams, as shown, the front, rear and side members being rigidly secured together to form the body of carriage 19 Seated on and rigidly secured to side members 24, 25 are rails 26 adapted to receive the wheels as of a kiln car or the like, the rails being each provided with an aliningstrip 26A fixed to the side. member. The body so formed is preferably additionally interconnected and braced by interme-.

diate upper and lower transverse brace members 27, 28, the braces 27, 28 being rigidly connected tothe opposite side members 24, 25.

Rotatably supported adjacent the upper ends of the posts 11, 13, as by brackets 29, are pulleys 31, 32, 33 and 34. Trained over the pulleys 31, 32, 33, 34, respectively, are cables .36, 37, 38, 39, the front cables 36, 37 being respectively secured to the inner side of front frame member 15' respectively adjacent the front posts 11, the connections being indicated at 41, 42. Similarly, the rear cables 38, 39 are connected to the rear frame member 17 respectively adjacent the rear posts 13,, these connections being indicated at 43, 44. It will be seen that the cables respectively extend upwardly from their;

connections to the frame members 15, 17, and pass over the respective pulleys upon which they are trained.

The cables respectively thence passdownwardly and are trained around pulleys carried on the outer faces of the front and rear frame members 15, 17 so that cable 36 passes around a pulley 46, cable 37 about a pulley 47, cable 38 about a pulley 4S, and cable 39 about a pulley 49, pulleys 46, 47 being rotatably supported from the front face of front framemember- 15, and pulleys 48,

F tented. pr- 5, .1960

49 being rotatably supportedt'rom the rearward face of rear frame member 17. From the respective pulleys 46, 47 the cables 36, 37 project transversely of the device along a line which is preferably diagonalled somewhat upwardly; Olfset to one side of the midline are a pair of pulleys 51, 52 which are respectively jonrnalledly supported from the front member 21"of carriage 19. These pulleys are disposed with one of the pulleys, as the pulley 51, having an edge portion slightly above the other pulley 52, and with these edge portions disposed in tangency so that when the cables are passed over the respective pulleys and project inwardly toward the carriage, the cables lie substantiallyin a vertical plane in parallelism. The cable 36 is passed about the pulley 51, and the cable 37 is passed about the pulley 52, and the cables 36, 37 pr'oject'inwar'dly from the pulleys 51, 52 to pass through a suitable aperture'54 formed in front carriage member 21. Thus the cables36, 37 are passed from their connection to the front frame member about the pulleys whic'hhave been described and into the interior of carriage 19.

'Similarly the cables 38, 39 project transversely of the device and are diagonalled somewhat upwardly in order to be trained about additional pulleys 56, 57, the pulleys 56, 57 being journalledly supported'from rear lift member 22. Preferably the pulleys 56, 57 are disposed in manner similar to the disposition of pulleys 51, 52 so as tolie approximatelyin tangency but with one of the pulleys, as the pulley 57, in overlying relationship to the iothe ififthe pulleys, as the pulley 56, with the result that the cables 38, 39, having passed beyond their training about the pulleys 56, 57, and inwardly toward the carriage, are disposed to lie in a substantially vertical plane in parallelism. Preferably the level of the uppermost rear pulley 57.is somewhat above the level of the forward uppermost pulley 51, and the level of the lowermost rear pulley 56 is below the level of the lowermost front pulley 52. The cables 38, 39 pass through suitable apertures formed in rear carriage member 22 ad thus project inwardly into the interior of the carriage area.

Within lift carriage 19 the lift activating mechanisms of the present device are preferably mounted and carried. These mechanisms include a forward hydraulic cylinder and piston assembly 59 which includes a rearwardly projecting piston rod 61. Cylinder and piston assembly 59 is disposed to lie substantially parallel to the longitudinal midline of the device and is offset to one side of such midline. There is further included a rear piston and cylinder assembly 63 including a forwardly projecting piston rod 65. The cylinder and piston assembly 63 is likewise disposed parallel to the longitudinal midline of the device and is offset from that midline oppositely to the offset of assembly 59. The cylinder of cylinder and piston assembly59 is rigidly fixed at its outer end to front carriage member 21, and the cylinder of assembly 63 is at its outer end rigidly fixed to the'rear carriage member 22;

The cylinders of these hydraulic assemblies respectively snugly fit between the cross braces 27, 28, and are secured thereto for enhancing the mounting of the cylinders in the device. Each of the piston rods 61, 65 is respectively connected with the piston of the piston and cylinder assembly with which it is associated and is adapted to be extended from the cylinder when the cylinder has been activated under energizing of the system.

To the rearward end of piston rod 61 a pulley bank 67 is affixed, and similarly to the forward end of piston rod 65 a pulley bank 69 is affixed. Each of the pulley banks 67, 69 comprises a plurality of pulleys which are preferably disposed in vertical alinement with each of the pulleys substantially horizontal and parallel with the others in the respective banks. In the present embodiment'each of the banks is shown as comprising four pulleys, althoughjtwillbe understood that in some in-i stances two or more of the pulleys may be combined together into a single pulley. Thus in the embodiment shown pulley bank 67 includes upper pulley 67A, lower pulley 67B and intermediate pulleys 67C, 67D. Similarly pulley bank 69 includes upper pulley 69A, lower pulley 69B and intermediate pulleys 69C, 69D.

In order to connect the respective pulley banks 67, 69 to the piston rods 61, 65 .yoke members 71, 73 are respectively connected to the distal ends of the piston rods. Each of the yokes comprises a substantially U-shaped body, and from the legs of the U-shaped body of the yoke 71 a pair of spacer collars 75 project rearwardly, and similarly from the U-shaped body of yoke 73 a pair of spacer collars 77 forwardly project.

Fixed to the collar spacers 75 of yoke 71 is a substantially vertically disposed shaft 79, and similarly fixed to the collar spacers 77 of yoke 73 is a substantially vertically disposed shaft 81. Pulleys 67A, 67B, 67C and 67D of pulley bank 67 are freely journalled on pulley shaft 79, and pulleys 69A, 69B, 69C and 69D of pulley bank 69 are freely journalled on pulley shaft 81. It will be seen that yoke collars 75 are respectively interposed between upper pulley 67A and intermediate pulley 67C, and between lower pulley 67B and intermediate pulley 67D, in order to hold the upper and lower pulleys separated from the intermediate pulleys, with the intermediate pulleys lying in close proximity. Similarly collars 77 are interposed between pulleys 69A, 69C and pulleys 69B, 69D for similar purpose to space the upper and lower pulleys 69A, 69B away from the intermediate pulleys with the intermediate pulleys being positioned in close proximity.

To the upper end of pulley shafts 79, 81, retainer caps 83, 84 are respectively fixed, serving to retain the pulleys against separation from the pulley shafts, and from the respective retainer caps switch trip bars 85, 86 respectively radially project along a line substantially parallel to the longitudinal midline of the device.

To the lower end of shafts 79, 81, preferably substantiallychannel shaped guide shoes 87, 88 are fixed, guide shoes 37, 88 serving to retain the pulley bank on its related shaft, and further serving as a guide for the reciprocal movement of the pulley bank and of the piston rods by which the pulley banks are carried. The shoes 87, 88 are respectively slidably engaged with guide rails 90, 91, which extend longitudinally of the device. Each of the guide rails 90, 91 preferably extends approximately throughout slightly less than half of the length of the device, guide rail 90 projecting rearwardly from a point approximately underlying pulley shaft 79, and being fixed to and supported on the rearrnost of lower cross braces 28, and at its rear end being rigidly fixed to rear carriage member 22. Guide rail 91 projects forwardly from a point approximately underlying pulley shaft 81, is supported on and fixed to the forwardmost of lower cross braces 28, and at its forward end is rigidly fixed to forward carriage member 21.

Thus the shoes 87, 88, which slidably embrace the rails 90, 91 provide a support for the respective pulley banks against sagging under the influence of gravity during operation and extension of the respective piston rods, and serve to maintain the pulley banks in alinement for reciprocation parallel to the longitudinal midline of the device. 1

For the purpose of activating the hydraulic cylinder and piston assemblies the present device includes an electric powered pump 93 having a motor 94, which is mounted to the body of lift carriage 19, preferably being mounted on the web of side member 24. The discharge portion of the pump 93 is connected by piping 95 through a check valve 95A to branch pipes 96, 97, which respectively lead to the pressure receiving ends of the cylinders of forward and rearward piston and, cylinder assemblies 59, 63. Thus the pressure developed by pump 93 may be delivered through valve 95A, which is'biased to block flow toward thepump, tothe pressure receiving ends of i the respective cylinders, and in well known manner efiect extension of the piston rods carried by the assemblies.

Pump 93 is connected by a return line 99 passing through a strainer 101 from a reservoir or tank 103. Piping 95 is connected by a bleed off line 105 to tank 103, a solenoid operated check valve 107 being interposed in line 105 so as to prevent flow therethrough under pressure from piping 95. An emergency bypass line 109 preferably is communicated with bleed ofi line 105 on the opposite sides of check valve 107, a manually operated valve 111 being interposed in bypass line 109 to control flow therethrough.

Fixed to and projecting forwardly from rear carriage member 22 is a support 113 upon which is mounted a normally closed limit switch 115 which is preferably provided with a suitable control arm disposed at the level of trip bar 85 and in longitudinal alinement therewith so that upon extension of piston rod 61 the trip bar carried by the pulley bank 67 is moved into engagement with switch 115 and is effective to open the switch and interrupt the circuit in which it is interposed. Similarly fixed to and projecting rearwardly from the forward carriage member 21 is an additional support 117 for a second normally closed limit switch 119. Switch 119 is likewise preferably provided with a suitable control arm which is disposed at the level of and in longitudinal alinement with trip bar 86 for engagement by the trip bar upon extension of piston rod 65 together with pulley bank 69 carried thereon so as to open switch 119 and interrupt the circuit in which it is interposed.

As best shown in Fig. 9, leads 120, 121 are connected to a suitable source of power such as the 110 volt terminals indicated at 123, a push button switch 124 being interposed in one of the leads, as the lead 120. Preferably limit switches 115, 119, normally closed by the force indicated by the arrows in Fig. 9, are interposed in series in one of the leads, as the lead 120, between switch 123 and motor 94. Thus it will be seen that with the switches 115, 119 normally closed the circuit to pump motor 94 may be completed by closing switch 124, thus energizing the pump motor, driving the pump 93 and effecting activation of the hydraulic system. switches 115, 119, or either of them, is opened, by impingement of the switch bars or otherwise, the circuit to the pump motor is broken, interrupting the delivery of pressure by the pump and deactivating the elevation of the carriage through the medium of the pump in the manner hereinafter described. When further activation of the pressure system is desired, the switches 115, 119 having normally closed, switch 124 may again be closed again energizing pump motor 94 and reactivating the system.

The activation of the hydraulic cylinder and piston assemblies is effective to elevate the supporting frame members 15, 17, and carriage 19 carried thereby, through the interaction of the pulley banks carried by the piston rods and the cables hereinabove described. As heretofore mentioned, cables 36, 37 pass through the aperture in front carriage member 21 into the interior of the carriage area. These cables extend rearwardly alongside the cylinder of assembly 59 and pass respectively around intermediate pulleys svc, 67D of pulley bank 67, passing around the rearward portion of the circumference of these pulleys. The cables 36, 37 pass thence forwardly substantially along the longitudinal midline of the device and pass around the forwardmost portion of the circum- When the ference of intermediate pulleys 69C, 69D of pulley bank 69, and thence extend rearwardly to an anchor bracket 125 to which cables 36, 37 are fixed as at 126. Anchor bracket 125 preferably spans between the rearmost upper and lower cross braces 27, 28, and is fixed thereto.

Cables 38, 39, as above stated, extend into the area of the carriage through rear carriage member 22 and extend forwardly alongside the cylinder of assembly 63 to pass around the forwardmost portion of the circumfer ence of upper and lower pulleys 69A, 69B of pulley bank 69, thence rearwardly along the longitudinal midline of the device in substantially vertical alinement in parallelism with the cables 36, 37 to pass around the rearmcst portion of the circumference of upper and lower pulleys 67A, 67B of pulley bank 67. Cables 38, 39 extend thence forwardly to an anchor bracket 128 which spans between and is rigidly fixed to the forwardmost of upper and lower cross members 27, 28. Cables 38, 39 are fixed to anchor bracket 128, as at 129, Fig. 3.

It will be observed that cables 36, 37 respectively pass through apertures formed in anchor bracket 12% intermediate the anchor points 129 in the passage of these cables to pass around pulley bank 67, and it will further be observed that cables 38, 39 pass through apertures formed in anchor bracket 125 to pass around the pulley bank 69. It further'will be seen that in the diagrammatic views, Figs. 5 and 7, that for purposes of illustration the points of fixing of the cables to their respective brackets have for purposes of illustration been illustrated as spread apart. In the preferred embodiment, as shown particularly in Figs. 3 and 4, the points of fixing of the cables to the anchor brackets are alined in vertical alinement, the showing in the diagrammatic views having been exaggerated for purposes of illustration.

In the operation and use of the device of the present invention with the parts thereof arranged substantially as hereinabove described, switches 115, 119 are normally closed and switch 124 is closed completing the electrical circuit energizing pump motor 94. With the motor thus energized valve 111 in bypass line 109 is likewise closed to block passage of fluid through the bypass line, sofenoid operated valve 167 being effective to block passage of fluid through line toward tank 103. Hydraulic fiuid under pressure is drawn toward pump 93 through return line 99 from tank 103 and is discharged under suitable hydraulic pressure through piping 95, and thence through branch pipes 96, 97 to discharge into the pressure receiving ends of cylinders 59, 63.

When thus activated the piston and cylinder assemb'ies are effective to thrust the piston rods 61, 65 and efiect rod extension from their respective cylinders, moving with them the pulley banks67, 69, the banks being moved in opposite directions of travel along parallel lines respectively offset to opposite sides of the longitudinal center line of the device, As the pulley banks are rcspecttive y shifted away from their related cylinders it is apparent that a tension is applied to each of the cables 36, 37, 3;

and 39, since the cables 36, 37 are fixed to anchor bracket and the cables38, 39 are fixed to anchor bracket 128. As the tension is increased on the cables the cables are efr'ectivethrough their respective connections; 41, 42, 43-

and 44 to exert a lifting pull on frame members 15 and 17 and on carriage-carried anchors 125, 128, causing same to rise along the front and rear posts 11, 13, and carrying with them the lift carriage 19 together with the instrumentalities mounted therein and carried thereby.

It will be seen that in virtue of the present arrangement of this invention an equal tension is exerted on all of thecables, even in the event that one of the piston and cylinder assembliesshould happen to lay because of some defect in the delivery of pressure thereto or other cause. Thus the tension is equally distributed to all corners of the device, resulting in an insurance that the frame and carriage carried thereby will be lifted le-velly and that tilting is substantially completely prevented.

As the piston rods are advanced away from their related cylinders, the respective pulley banks carried by the piston rods are supported by the interengagement of the shoes 87, 88 with guide rails 90, 91 eliminating the possibility of sagging of the piston rods under the weight of the pulley banks carried by the distal ends thereof. Additionally, the shoes are effective to prevent any lateral deviation in the travel of the respective pulley banks,

maintaining the same to travel in a line parallel with the longitudinal midline of the device in the reciprocation of the pulley banks under operation of the cylinder and piston assemblies. a

If it is desired for some unusual circumstance to interrupt the upward travel of the lifting mechanism the same may be accomplished by opening any of the switches 115, 119, 124, interrupting the circuit energizing pump motor 94, and accordingly arresting the elevation of the frame members and carriage.

When the pulley banks have been shifted to full extended position the cables will have been drawn to the fullest state of tension and the connection points 41, 42, 43, 44 will have been moved upwardly by the shift of the cables through the pulleys 31, 32, 33, 34 a distance which is substantially equal to twice the sum of the extended lengths of the piston rods, and this distance is of sufficient length to move the carriage to the full raised position illustrated diagrammatically in Fig. 8, with the pulley banks reaching the full extension position as illustrated diagrammatically in Fig. 7. which corresponds with the elevated position shown in Fig. 8. The trip bars 85, 86 are respectively moved into contact with the limit switches 115, 119, engage against the switch controls, and effect opening of the switches, interrupting the circuit energizing motor 94, and accordingly interrupting further possibility of travel upwardly of the device.

With the device in this full elevated position the load,

carried as for example on rails 26. may be moved from the lift and it is then desirable to return the lift to the at rest position as illustrated in Figs. 1 and 2. To accomplish this purpose, valve 107 in bleed off line 105 may be opened by the operation of its solenoid control 130 providing for an escape of the fluid from the system to return into tank 103. As shown in Fig. 9, solenoid 130 is coupled by leads 131, 132 to leads 120, 121, and thus to terminals 123. A push button switch 133 is interposed as in lead 131 and the solenoid is energized for valve operation upon closure of switch 133."Under the influence of the weight of the elevated'device, urged downwardly by gravity, the'cables are effective to act on the pulley banks and thus to urge the piston rods to return into the cylinders of the'cylinder and piston assemblies, correspondingly shifting the pistons of the assemblies toward the fluid contained therein and effecting a forcing of the fluid outwardly through the branch pipes 96, 97 to discharge through bleed off line 105, and thence into tank 103. It will be observed that bleed off line 105 is of a diameter substantially smaller than the diameter of piping 95 and branch lines 96, 97. The effect of the reduced size of the bleed off line is torestrict the return flow into the tank, resulting in maintaining the descent of the device from its elevated position to be accomplished at 'a substantially slow rate of speed. In the event of failure of electric power with the lift carriage elevated, manual valve 111 in bypass 109 may be opened permitting discharge of fluid from the cylinders to the tank bypassing solenoid valve 107.

When it is desired to again operate the device the switches 115, 119 being normally closed after release by the trip bars, switch 124 may again be closed, the circuit reestablished, and pump motor'94 reenergized with the procedure as described hereinabove being thereafter substantially repeated.

It, will, therefore, be seen that the present invention cut drawings and de'scriptiomeach of the pulley banks comprises an abutment, and it will be observed that each of these pulley bank abutments is movable relative to the other of the pulley bank abutments. Thus, if for example one of the hydraulic cylinder and piston assemblies of the present invention becomes inoperative, its related pulley bank continues as an abutment relative to which the remaining pulley bank is shiftable, and which accomplishes an equal tensioning upon the cables from the respective corners of the present quadrilateral device. It will, therefore. be understood that the present invention is not intended to be limited to the precise form shown in the present application, except insofar as it is limited by the appended claims. an operable structure may be achieved by the utilization of a single hydraulic cylinder and piston assembly'comparable to that described herein, with the utilization of a relatively fixed abutment such as would otherwise be provided in the event of the failure of one or the other of the assemblies in the preferred emhodimeritshown.

Inasmuch as the heig t of lift achieved is equal to twice the total length of piston rod abutment extension, it is apparent that for low lifts a single piston and cylinder assembly may in many circumstances be highly appropriate. Similarly, where space permits, a lift height equivalent to that illustrated in the present preferred embodiment may be achieved by lengthening of the piston rod of a single assembly. Similarly, in some circumstances, it is found to be desirable to utilize more than two hydraulic cylinder and piston assemblies, as for example, by disposing three or more cylinder and piston assemblies in alternately oppositely directed positions. It will be seen that with the utilization of additional hydraulic cylinder and piston assemblies the length of the overall mechanism may be lessened while maintaining lift height equivalent to that shown in the present embodiment. Additionally, under some circumstances, it may prove desirable to provide a pair of hydraulic cylinder and piston assemblies disposed for thrust in the same direction, in which circumstance a fixed abutment, preferably in the form of a fixed bank of pulleys, may be interposed between the movable pulley banks with the cables trained thereabout and accomplish an operation substantially equivalent to that described herein.

It will further be understood that. while the abutment means have been herein shown and described as pulley banks, other equivalent abutment means may be substituted therefor. It further will be understood that, while the cables have been described as deadended to the carriage frame, the length of lift produced by the piston stroke may be accentuated by shifting such deadending to the lift support posts, although under such circumstances the lifting power is somewhat minimized.

It accordingly will be seen that the present invention provides a highly useful system for lift means which is susceptible of many equivalent embodiments without departing from the scope of the present invention.

I claim:

1. In a lift, a lift carriage comprising a frame, a pair of hydraulic cylinder and piston assemblies horizontally disposed within and secured to said frame, each said assembly including a piston rod and being positioned with i the distal ends of said piston rods projecting respectively comprises a hydraulically motivated cable lift in which abutment, the movable abutment being movable relative to the other abutment just mentioned. In the preferred embodiment, as illustrated in the presrearwardly and forwardly of said frame, a first and second pulley bank each comprising a plurality of pulleys, means journally supporting said banks and respectively connecting said first bank to the distal end of the rearwardly projecting piston rod and said second bank to the distal end of said forwardly projecting piston rod, a front pair of vertical supportsat the front of said carriage, a. rear pair of vertical supports at the rear of said carriage, front and rear cables respectively supported from an elevated portion of said supports. one end 'of said front cables being anchored adjacent the front of said lift and one end of saidv rear cables being anchored Thus, for example,

adjacent the rear of said lift, said front cables extending rearwardly through the front of said frame into the interior of said carriage and being trained successively around said first and second pulley banks with their other ends being anchored Within said frame rearwardly of said second bank, said rear cables extending forwardly through the rear of said frame into the interior of said carriage and being trained successively around said second and first pulley banks, the other ends of said rear cables being anchored within said frame forwardly of said first bank, said pulley banks being relatively oppositely shiftable under the influence of said assemblies to exert tension on said cables and effect elevation of said carriage relative to said supports, guide shoe means connected respectively to each said pulley bank, guide rails mounted in said carriage alined with the line of shift of said banks, said shoe means engaging said rails to guide and support said banks during shift.

2. In a lift, a lift carriage comprising a frame, a pair of hydraulic cylinder and piston assemblies horizontally disposed within and secured to said frame, each said.

assembly including a piston rod and being positioned with the distal ends of said piston rods projecting respectively rearwardly and forwardly of said frame, a first and second pulley bank each comprising a plurality of pulleys, means journally supporting said banks and respectively connecting said first bank to the distal end of the rearwardly projecting piston rod and said second bank to the distal end of said forwardly projecting piston rod, a front pair of vertical supports at the front of said carriage, a rear pair of vertical supports at the rear of said carriage, front and rear cables respectively supported from an elevated portion of said supports, one end of said front cables being anchored adjacent the front of said lift and one end of said rear cables being anchored adjacent the rear of said lift, said front cables extending rearwardly through the front of said frame into the interior of said carriage and being trained successively around said first and second pulley banks with their other ends being anchored within said frame rearwardly of said second bank, said rear cables extending forwardly through the rear of said frame into the interior of said carriage and being trained successively around said second and first pulley banks, the other ends of said rear cables being anchored Within said frame forwardly of said first bank, said pulley banks being relatively oppositely shiftable under the influence of said assemblies to exert tension on said cables and effect elevation of said carriage relative to said supports.

3. In a lift, a lift carriage comprising a frame, a pair of power means disposed within and secured to said frame, a first and second pulley bank each comprising a plurality of pulleys, means journally supporting said banks and respectively connecting said first bank and said second bank to said power means, a front pair of vertical supports at the front of said carriage, a rear pair of vertical supports at the rear of said carriage, front and rear cables respectively supported from an elevated portion of said supports, one end of said front cables being anchored adjacent the front of said lift and one end of said rear cables being anchored adjacent the rear of said lift, said front cables extending rearwardly through the front of said frame into the interior of said carriage l0 and being trained successively around said first and second pulley banks with their other ends being anchored within said frame rearwardly of said second bank, said rear cables extending forwardly through the rear of said frame into the interior of said carriage and being trained successively around said second and first pulley banks, the other ends of said rear cables being anchored within said frame forwardly of said first bank, said pulley banks being relatively oppositely shiftable under the influence of said power means to exert tension of said cables and effect elevation of said carriage relative to said supports.

4. In a lift, a pair of transversely aligned and spaced apart front vertical supports, a pair of similarly trany versely alined and spaced apart rear vertical supports spaced longitudinally rearwardly from said front supports, said supports defining a substantially rectangular area, a lift carriage in said area, cables supportingly coupling said carriage to said supports, a front pair of said cables extending respectively from said front supports rearwardly into said carriage, a rear pair of said cables extending respectively from said rear supports forwardly into said carriage, a pair of substantially horizontally disposed hydraulic cylinder and piston assemblies mounted in said carriage, each including a piston rod, one said piston rod projecting rearwardly of said carriage and the other said piston rod projecting forwardly of said carriage, abutment means comprising a pair of pulley banks respectively mounted on the distal ends of and movable with said piston rods, said front and rear cables being trained about said pulley banks and being tensioned by the relative movement of said pulley banks under the influence of said assemblies, to effect raising of said carriage relative to said supports.

5. In a lift, a pair of transversely alined and spaced apart front vertical supports, a pair of similarly transversely alined and spaced apart rear vertical supports spaced longitudinally rearwardly from said front supports, said supports defining a substantially rectangular area, a lift carriage in said area, cables supportingly coupling said carriage to said supports, a front pair of said cables extending respectively from said front supports rearwardly into said carriage, a rear pair of said cables extending respectively from said rear supports forwardly into said carriage, a pair of substantially horizontally d sposed hydraulic cylinder and piston assemblies mounted in said carriage, each including a piston rod, one said piston rod projecting rearwardly of said carriage and the other said piston rod projecting forwardly of said carriage, a pair of pulley banks respectively mounted on the distal ends of and movable with said piston rods, said front and rear cables being trained about said pulley banks and being tensioned by the relative movement of said pulley banks under the influence of said assemblies, to effect raising of said carriage relative to said supports.

References Cited in the file of this patent UNITED STATES PATENTS 410,533 Clayton Sept. 3, 1889 2,408,757 Dunlop Oct. 8, 1946 2,538,517 Hayden Ian. 16, 1951 FOREIGN PATENTS 462,735 Great Britain Mar. 15, 1937 

